Sliding contact device for tuning coils



J c. P. MAJKRZAK sunmc cormcw DEVICE FOR TUNING-COILS Jiily 14, 1959 3Shets-Sheet 1 1 Filed Oct. 10, 1955 INVENTOR (l/ARIES e "4.1mm BY CAGENT July 14, 1959 c. P. MAJKRZAK 5 sunmc CONTACT DEVICE FOR TUNINGcons Fil ed Oct. 10, 1955 s Sheets-Sheet 2 INVENTOR (l/ARIES 8 "AdkkakiENT - 222g 2:255:5 m \m 1 c. P. MAJKRZAK SLIDING CONTACT DEVICE FORTUNING COILS Filed Oct. 10, 1955.

July 14, 1959 3 Sheets-Sheet 5 Wbm R 0W6 T T w E Hawk w m B UnitedStates Patent SLIDING CONTACT DEVICE FOR TUNING COILS CharlesP.',Majkrzak, Newark, N.J., assignor to International Telephone andTelegraph Corporation, Nutley, N.J., a corporation of MarylandApplication October 10, 1955, Serial No. 539,629 12 Claims. (or.336-116) This invention relates to sliding contact devices for tuningcoils and more particularly to a sliding contact device for operationbetween two concentric tuning coils wherein one of the coils may bemovable with respect to the other of the coils.

In the copending application of R. T. Adams et al., Serial No. 476,416,filed December 20, 1954, entitled A Sliding Contact Device for TuningCoils, there is disclosed a sliding contact device for encircling atuning coil including a band of corrugated material having a pluralityof contact elements disposed in spaced relation circumferentiallythereof for engagement with the turns of a tuning coil. The corrugatedshape of the band gives the contact device a resilient characteristicwhich permits outward radial and circumferential freedom to enable thecontact elements to follow variations in the surface of the coil and/ormisalignment of the axis of the band and the tuning coil.-

The sliding contact device of the aforesaid copending application isextremely useful where the outward radial and circumferential freedom isnot restricted, such as would occur when utilized within a tuning coilor between two concentrically-disposed tuning coils. In these twogeneral applications, the tuning coil surrounding the sliding contactdevice would restrict its freedom of movement and thereby counteract theresilient characteristic of the sliding contact device.

Therefore, it is an object of this invention to provide a slidingcontact device whose resilience will not be counteracted by theconfinementof a tuning coil disposed relative thereto.

Another object of this invention is to provide an improved slidingcontact device for tuning coils which provides substantially constantcontact pressure as said device is, moved over variations in the surfaceof the coil.

.Still another object of this invention is to provide a sliding contactdevice having a plurality of contact areas on either one or both sidesof said device whose resilient characteristic-will enable themaintenance of constant contact pressure as said device is moved overvariations in the surface of the coil regardless of whether said deviceis disposed to encircle the coil, disposed to be within the coil, ordisposed between two concentrically-disposed coils, one of said coilsbeing movable with respect to the other of said coils.

, A feature of this invention is the provision of a firsttubular'member, a second tubular member of smaller diameter than saidfirst member disposed concentrically therein and a curved end portioninterconnecting adjacent ends of 'said first and second members, theside wall of at least one of said members being of conductive materialand having spaced slots disposed generally axially thereof toprovide aplurality of contact areas spaced circumferentially thereof, the slotsbeing extended into said curved interconnecting portion.

Another feature of this invention is the provision of an assemblyincluding two devices, as described above,

fastened together to dispose the contact areas of each de-- 2,895,115Patented July 14, 1959 2 vice on opposing sides of said assembly and inan engagement relation with the turns of two concentricallydisposedtuning coils, said assembly being utilized wherein the spacing betweenthe concentric coils is at least equal areas of each member enabling aconstant contact pressure between the turns of each one of twoconcentricallydisposed tuning coils and the sliding contact.

Other features of this invention include the utilization of flexiblematerial for said tubular members and-said curved interconnectingportion to provide the contact areas with a resilient characteristic,the forming of said tubular members adjacent the ends of said slotsremoved from said curved interconnecting portion to provide a flexingmember to cooperate in establishing the resilient characteristic of saidcontact areas, and the forming of the edges of said spaced slots toprotrude away from said contact areas to prevent said slots from scoringthe tuning coil in movement of the sliding contact device therealong.

The above-mentioned and other features and objects of this inventionwill become more apparent by reference to the following descriptiontaken in conjunction with the accompanying drawings, in which:

Fig. 1 is an elevational view of the contact device of this invention;

Fig. 2 is an end view of an embodiment of the sliding contact device ofthis invention taken along line 2-2 of Fig. 3;

Fig. 3 is a longitudinal cross-sectional view taken along line 3-3 ofFig. 2;

Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 2;

Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 2;

' Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 2;

Fig. 7 is a cross-sectional view taken along line 7-7 of Fig. 4;

Figs. 8, 9 and 10 are diagrammatic views of other em-I bodiments of thesliding contact device of this invention; and

Fig. 11 is a plan view of the material from which the contact device ofthis invention is formed.

Referring to Figs. 1-7, inclusive, contact device 1 is illustrated ascomprising a tubular member 2, a tubular member 3 of smaller diameterthan member 2 and "a curved end portion 4 connecting members 1 and 2together at adjacent ends thereof to form a single unit. The members 2and 3 and portion 4 include as material thereof a spring metal, such asberyllium copper, to impart a resilient characteristic to device 1. Toprovide contact areas, the appropriate ones of members 2 and 3' areslotted axially thereof, with these slots extending into the curvedportion 4. The member slotted depends upon the utilization of device 1.If device 1 is used within a tuning coil, member 2 would be slottedwhile if device 1 is employed to encircle a tuning coil, member 3 wouldbe slotted to provide the desired plurality of cir cumferentially-spacedcontact areas.

Device 1 finds its greatest utility in its employment as a contactingdevice between concentrically-disposed c'oils 5 and 6, as illustrated inFig. 2. In this utilization, member 2 would be slotted, as indicated byslots 7, and member 3 would be slotted, as indicated by slots 8. Slots 7provide a plurality of contact areas .9 in member 2, with cooperates to'render device 1 resilient. The slots Tand 25* extend along the entirelength of contact areas-9 and 10, and at a-point' adjacent the rearwardedge of contact areas 9 and 16, the slots 7 and 8 are again given aV-shaped con-' figuration, as illustrated at 11 in Fig. 1. Coextensivewith V-slbt'll is afiexure member 12 which renders therearwardedge ofcontact areas 9 and 10 flexible that amount necessary to followvariations in the surface'of the-coil andrnaintain members-2 and 3parallel toeach-other:

when-inoperation. Itwill be'obse'rved that the contact are of member Zis in an'ove'rlying relationship with respect toslots 8 of member '3,and, convers'e1y,'slots*7 of member'Z'are in an overlying relationshipwith respect to contact areas 10 of member 3.

Extending from the line defined by'the members 12 and-the V-slots 11 isastrip of material 13 which secures device 1 to a means for movingdevice 1 longitudinally ofcoils Sand 6.' This means for moving device 1includes-a disk 15 having-an axially-disposedcylinder 16 to which isspot welded securing strips 13. Disk 15 inchldesa threaded aperture 17therein which accepts screw 18. Screw 18 'is fixed at one end thereof inflange'19 of coil form 5a and includes at the other end thereof aspline- 211: passing through collar 21 which is driven by motor drive22. Flanges 19 and 23 include threaded apertures '24 and 25for receiptof screw' 26 therein. sci-ewes is-driven by motor drive 27 which,through the action'of form 5d and screw 18, drives both'coilS and device1 axially with respect to coil 6"for adjustment of the number of turnswhich are shorted or'grounded' out by device 1. By operating motor drive22, the screw18'is rotated through means of spline 20 to move device 1relative to coil 5 and coil 6 independent'of coil 5. The means formovement disclosed in Fig. 3 is one" half of the total gearingarrangement employed to provide the desired movement, the other halfbeing located on the other side of the axis of concentricity (notshown). and receiving their motive power from motors 22' and 27.Themeans' to move contact device 1 is not restricted to the meansdisclosed in Figs. 2 and 3; other arrangements for'the desiredaxial orlongitudinal movement will be obvious to those skilled in the art. Itshould be understood that the relative movement of coils 5 and 6 is notlimited to the movement of coil 5 but may be caused by movement of coil6.

Asm'entio'ned hereinabove', device 1 may have them her 2 slotted forutilization for engagement of acoil-su'r rounding" device 1, or member3"may beslotted'for engagement with the turns of a'coil aboutwhichdevice 1 is disposed. It is preferable to achieve the optimumresilience of device 1 that'each one of'members'Z and 3 be slotted, asillustrated in Figs. 1 and 2, regardless of whether device 1 is utilizedbetween two concentricallydisposed coils, within a c'oilor encircling acoil. The differeiicebetween thedevice l for each one of the differentapplications may be the location of'the conductive material on thecontact members. In other words, for utilization between two concentriccoils, contact areas 9 and 10 would have a conductive characteristic.For utilization within a tuning coil,.contact area 9 would have aconductive characteristic, and for utilization about a tunin'geoil,contact area 10 would have a-- conductive characteristic. I, p w 7 Asmentioned hereinabove, theslots 7- and 8 are-extended into portion 4just short of-contact areas 9 and 10. is illustratedin greater detail inFigs. 4 and 5. This provides a curved leading edge 29 for member 2 and acurvedleading edge 30 for member 3 which prevents scoring. or cuttingthe wire formingthe' turns of -atuning 'coil. The slots 7 and 8 inportion 4 and the V-shaped slots l-l in the member 12 are conducive toair flow therethrough for purposes of cooling.

Contact areas 9 and 10 have their edges adjacent slots 7 and 8,respectively, turned inwardly, as illustrated by the ribbed portions 31and 32, which extend the entire length of contact areas 9 and 10,respectively. This inwardly-turned edge of areas 9 and 10 provides astiffening effect therefor but yet not to that extent that these areascannot follow variations in the surface of the coil. The ribbed portions31 and 32 do extend into portion 4 and into member 12.- Theunribbedrportions, as indicated at 33 and 34, enable a deflection ofdevice 1 to cause a change in the thickness thereof designated t, asillustrated in Fig. 6. Fig. 6illustrates the'extent to'whichtheseunn'bbed sections .33and 34 enable contact device 1 to deflect. Undernormal use, device 1 has a thickness t as defined by the solid linerepresentation of members 2 and 3 and portion 4. Under an unloadedcondition, members 2, 3 and iwill' assume the configuration (greatlyexaggerated) illustrated by the dotted representation thereof, thusindicating the amount" of resilience present in the sliding'contactdevice of this invention. It will be further noted that the length ofthe contact device'l changes between the normal' loaded condition andthe unloaded' condition, as designated bya'l in Fig.6;

Itwill be observed in the detailed sections illustrated in Figs. 4, 5,6'and 7 that the material from which device 1 is'formed is preferably alaminated stock'including a conductive metal portion 35' and aspringjmetal portion 36. In a reduction to practice, theconductive metalportion was coin silver whichis' an alloy of silver and 10% copperand'thespring metal portion was beryllium copper.

As mentioned hereinabove, device 1 has 'as its principal utilization ashorting means for tuning coils especially disposed between twoconcentric coils where one coil is movable with respect to the other andespecially where the necessary spacing between these coils is of alimited nature; However, as pointed out hereinabove, the application ofdevice 1 isnot limited to utilization between concentrically-disposedcoils but may be utilized to pro vide' a moving, short on the outersurface :of a tuning coilor on the inner'surfaceof atuning coil.

Referring to Fig.8, there is disclosed therein the utilization ofcontact device 1 as a moving short for 'a single coil which inthisinst'ance'is disposed on the 'innersurface of device 1 in engagementwithmember 32 To utilize device 1 in conjunction with coil 37, it isnecessary to provide a compression ring 38 fixed to member -2 in amannerto load the sliding contact device 1 and thereby place theresilientcharacteristic thereof in operation to follow'variationsin thesurface'of coil 37.

The disclosureof Fig. 8 is meant to sufiice'to illustrate the employmentof device 1 when the coil 37 is disposed about device 1. Inthisinstance, the radius of "curvature of' each of the elements"disclosed therein would be re versed, and the compression ring 38 wouldbe within coil 37 rather than about coil 37, as disclosed in Fig. 8.

Referring to Figs. 9 and 10, there is disclosed two embodiments ofasliding contact assembly 39 which employs two shding contact devicesIt: and 1b identical in nature to sliding contact device 1, describedhereinabove. As-' sembly 39 is formed by securing the'outer memberlb'of. device 1b to the innermember 3a of device 1a, as indicated at 40. Inassembly 39 there will still be the same flexure members to enable thecontact assembly to follow'variations in the two concentrically-disposedcoils 41 and42, substantially as-described hereinabove in connectionwith-device 1. Assembly 39- enables the utilization ofa contact deviceof this invention where the sp ac-. ing of the coils Hand 42 isgreaterthan can be accom modated by a single one of the contact devices of.this invention.

Fig. 10 illustrates a similar arrangement, as diclosed in Fig. 9, withthe exception that the radius of curvature of portions 4c and M has beenmodified to separate the leading edge of assembly 39a which enables theaccommodation of concentric coils 41a and 42a which have a greaterspacing therebetween than is present in the arrangement of Fig. 9. Themodification of portion 4, as disclosed in Fig. 10, further provides agreater resilient characteristic at the leading edge of assembly 3911.

Referring to Fig. 11, there is disclosed a sheet of material which haspunched therein slots 7 and 8 including the V-shaped portions 11. In thepunching operation of the sheet material 43, the edges of slots 7 and 8are ribbed or, in other words, turned away from the contact surfaces 9and 10, as indicated by dotted lines 44. Certain ones of slots 8 arecontinued from the V-shaped portion 11 outwardly to the end of the sheet43, as indicated by slot 45, which enables the member 3 to conform tothe diameter to which device 1 is fitted and maintain a parallelrelationship between members 2 and 3.

" The first step in forming device 1 includes formation of the flexuremembers 12 by appropriately bending sheet 43 along lines 46 and 47. Thenext step is the bending of sheet 43 about the center line 48 to formportion 4 to have a given radius of curvature. The thusly-formed linearpiece is cut to a desired length to encircle the tuning coil 6, asdepicted in Figs. 2 and 3, which thenv forms the tubular members 2 and 3as described hereinabove. The tubular device 1 is spot welded orotherwise secured to cylinder 16 to form a continuous band of material.In practice, contact device 1 is held in a welding fixture at thedesired" inside and outside diameter to fit between concentric coils,said device being placed under a loaded condition. Flange 16 is thenWelded to strips 13 to provide the contact device with the propercontact pressure and diameters and the desired means for relativemovement thereof.

While I have described above the principles of my invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of my invention as set forth in the objects thereof and inthe accompanying claims.

I claim:

1. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of smaller diameter thansaid first member disposed concentrically therein, a curved end portioninterconnecting one end of said first member to the adjacent end of saidsecond member, means connecting together the other ends of said membersat a point intermediate said members and axially opposite said curvedportions, the side wall of one of said members being of conductivematerial and having spaced slots disposed generally axially thereof toprovide a plurality of contact areas spaced circumferentially thereof toengage turns of a coil, said slots being extended into said curvedinterconnecting portion.

2. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of smaller diameter thansaid first member disposed concentrically therein, and a curved endportion interconnecting one end of said first member to the adjacent endof said second member, means connecting together the other ends of saidmembers at a point intermediate said members and axially opposite saidcurved portions, the side wall of one of said members being ofconductive material and having spaced slots disposed generally axiallythereof to provide a plurality of contact areas spaced circumferentiallythereof to engage turns of a coil, said slots being extended into saidcurved interconnecting portion, certain of said slots including V-shapedportions at the ends thereof, the bases of the V-shaped portionscomprising the ends of the slots.

3. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of smaller diameter thansaid first member disposed concentrically therein, and a curved endportion interconnecting one end of said first member to the adjacent endof said second member, means connecting together the other ends of saidmembers at a point intermediate said members and axially opposite saidcurved portions, the side wall of one of said members being ofconductive material and having spaced slots disposed generally axiallythereof to provide a plurality of contact areas spaced circumferentiallythereof to engage turns of a coil, said slots being extended into saidcurved interconnecting portion, said slots including V-shaped portionsat the ends thereof, certain of said V-shaped portions extending intosaid curved interconnecting portion, and the bases of the V-shapedportions comprising the ends of the slots.

4. A device according to claim 3, wherein said one of said membersincludes a portion adjacent the end of said slot removed from saidcurved interconnecting portion having a segment thereof extendinginwardly from said contact areas, others of said V-shaped portions beingcoextensive with said inwardly-extending segment.

5. A sliding contact assembly comprising two contact devices as definedin claim 2, one of said contact devices being disposed concentrically ofthe other with the outer wall of one engaging the inner wall of theother.

6. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of smaller diameter thansaid first member disposed concentrically therein, and a curved endportion inter connecting one end of said first member to the adjacentend of said second member, means connecting together the other ends ofsaid members at a point intermediate said members and axially oppositesaid curved portions, the side wall of both of said members being ofconductive material and having spaced slots disposed generally axiallythereof to provide a plurality of inner and outer contact areas spacedcircumferentially thereof to engage turns of two concentrically-disposedcoils, the slots of each of said members being extended into said curvedinterconnecting portion.

7. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of smaller diameter thansaid first member disposed concentrically therein, and a curved endportion interconnecting one end of said first member to the adjacent endof said second member, means connecting said members together at adistance removed from said curved interconnecting portion, the side wallof both of said members being of conductive material and having spacedslots disposed generally axially thereof to provide a plurality of innerand outer contact areas spaced circumferentially thereof to engage turnsof two concentrically-disposed coils, the slots of each of said membersbeing extended into said curved interconnecting portion, each of saidmembers includes a portion adjacent the end of said slots removed fromsaid curved interconnecting portion having a first segment thereof at adiameter intermediate the diameters of said first and second members anda second segment thereof joining said contact areas with said firstsegment, said second segment extending inwardly from said contact areas.

8. A device according to claim 7, further including means to move saidcontact device axially of said tuning coils, said means to moveincluding a member concentric to said tuning coils having an annularflange member extending therefrom radially of said tuning coil and meansto secure said first segment to said flange member.

9. A device according to claim 7, wherein said slots include V-shapedportions at the ends thereof, certain of said V-shaped portionsextending into said curved interconnecting portion and others of saidV-shaped portions being coextensive with said second segment.

10. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member of-smaller diameter thansaid first member disposed concentrically therein, a first curved endportion inter.- connecting one end of said first member to the adjacentend of said secondmember, a third tubular member of smaller diameterthan said second member disposed concentrically therein, a fourthtubular member of smaller diameter than said third member disposedconcentrically therein, a second curved end portion interconnecting oneend of said third member to the adjacent end of said fourth member,means securing said third member to said second member, the side Wall ofsaid first and fourth members being of conductive material and havingspaced slots disposed generally axially thereof to provide a pluralityof contact areas .spaced circumferentially of said first andfourtbmembers to engage turns of two concentrically-disposed coils, the slotsof said first and fourth members being extended into their associatedcurved interconnecting portion.

11.. A sliding contact device for inductive tuning coils comprising afirst tubular member, a second tubular member ofv smaller diameter thansaid first member disposed concentrically therein, and a curved endportion interconnecting one end of said first member to the adjacent endof said second member, the side Wall of one of said members being ofconductive material and having spaced slots disposed generally axiallythereof to provide a plurality of contact areas spaced circumferentiallythereof to engage turns of a coil, said slots being extended intosaidcurved interconnecting portion, the slots in said first membersbeing staggered with respect to the slots in said second member wherebythe contact areas of each of said members are in an overlyingrelationship with the slots,

interconnecting portion, the side wall of both of said.

members being a conductive member and having spaced slots disposedgenerally axially thereof to provide a plu-...

rality of inner. and outer contact areas spaced circumferentiallythereof to engage turns of said concentrically disposed coils, the slotsof each of said members beingv extendedinto said curved interconnectingportion, and further including means to move said contact device axiallyof both said coils, and means to move one of said coils and saidcontactdevice as a unit axially with respect to the other said tuning coil.

References Citedin the-file of this patent UNITED STATES PATENTS2,379,047 Thomas Tune 26, 1945 2,426,429 Bels Aug. 26, 1947 2,486,285Hurst Oct. 25, 1949 2,523,725 Schmidt Sept. 26, 1950 2,658,098. Colemanet al. Nov. 3, 1953 2,742,617 Bondley Apr. 17, 1956 2,760,177 Hollis etal Aug. 21, 19,56

